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Vol. 52, 2013
Low phylogeographic structure of Rhinella arunco (Anura: Bufonidae), an
endemic amphibian from the Chilean Mediterranean hotspot
Dayana
Vásquez1, Claudio Correa1,2*, Luis Pastenes1,
R Eduardo Palma2 and Marco A Méndez1
1Laboratorio
de Genética y Evolución, Facultad de Ciencias, Departamento de Ciencias
Ecológicas, Universidad de Chile, Las Palmeras, 3425 Santiago, Chile
2Laboratorio de Biología Evolutiva, Departamento de
Ecología, Pontificia Universidad Católica de Chile, Alameda 340,
Santiago, Chile
Abstract
Background: The Mediterranean zone
of central Chile (30° to 38°S) is one of the 25 diversity hotspots in
the world. However, there are few phylogeographic studies which
identify the factors that have influenced population diversification in
the fauna of this area. In this study, we investigated the
phylogeographic structure of Rhinella arunco, an anuran endemic to
Mediterranean Chile, using 160 individuals from 23 localities
representative of its entire distribution (32° to 38°S).
Results: The haplotype network revealed four
haplogroups, three of which overlap geographically and only one of
which has an exclusive geographic distribution. An analysis of
molecular variance indicated that neither watershed limits nor the main
rivers in the current distribution of this species have been important
geographic barriers against the dispersion of individuals. Finally, the
Geneland analysis showed three population units, one of which concurs
with one of the haplogroups found in the haplotype network. Together,
these analyses indicated a low level of phylogeographic structure for
this species. On the other hand, the highest levels of
intrapopulational genetic variation were concentrated in the central
part of the distribution (33° to 34°S), which may indicate an effect of
Pleistocene glaciations on the genetic diversity of the populations in
the extreme south of its range.
Conclusions: The low
phylogeographic structure observed in R.
arunco is a rarely documented pattern for amphibians and
contrasts with the phylogeographic studies of other vertebrates which
inhabit the same zone. This result may be attributed to a series of
attributes of bufonids, related mainly to water retention and their
reproductive biology, which have allowed them to disperse and colonize
an enormous variety of environments.
Key words: Phylogeography; Central Chile;
Mitochondrial DNA; Pleistocene glaciations.
*Correspondence: E-mail: ccorreasp@gmail.com
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